PERFORMANCE

FIELD OF THE INVENTION

[0001] The subject matter of the present invention relates to an end of trailer fairing and system that improves aerodynamic performance of the trailer. More particularly, the present application involves an end of trailer fairing that features a top fairing, side fairings, front trailer skirts, and rear trailer skirts.

BACKGROUND OF THE INVENTION

[0002] Trailers towed by trucks and similar apparatuses for transporting cargo can be large, unwieldy, and include geometries which invite inefficiencies during travel. One aspect of these inefficiencies concerns the aerodynamics of the trailer. For maximum capacity, the trailer is box shaped which is not the most aerodynamically available option. Further, the rear door of the trailer is made in a particular manner to facilitate loading and unloading, such as utilizing a large opening, and the rear door may not have optimal aerodynamic properties. In an effort to improve trailer aerodynamics, trailers have been built, supplemented, or retro-fitted with trailer skirts (or side skirts), devices affixed to the underside which limit air circulating in the empty space between the trailer’s axles. By reducing the amount of airflow in this space, drag caused by turbulence is reduced and permits the trailer to be towed more efficiently, increasing the gas mileage and performance of the vehicle and its cargo. Other ways of improving aerodynamic performance of the trailer involves the provision of fairings to the end of the trailer. The fairings modify the airflow around or off of the end of the trailer to reduce drag. It is known to produce fairings that extend a good bit (5 inches or more) off the back end of the trailer for the purposes of reducing drag. Boat tails are devices arranged at the back end of the trailer to help converge and stabilize the wake at the back of the trailer for improved aerodynamic performance.

[0003] Combining all of these various aerodynamic elements is problematic because the local aerodynamics of the vehicle are impacted by the geometry of the entire vehicle. Some devices may improve performance when used by themselves, but have no impact on performance when used with other devices. This may be because a particular component is designed to maximize its individual contribution to fuel savings, and is not designed to work together optimally with other components in the system. Aerodynamic components of a trailer that include moving parts will require maintenance, and drivers may be required to remember to deploy some other types of aerodynamic devices. Also, the placement of various devises far off the back end of the trailer adds to the length of the trailer increasing the risk of damage to these components and surrounding vehicles. It would be desirable to have an aerodynamic system that incorporates a trailer end fairing and other components in an optimal manner for purposes of increasing the aerodynamic performance of the trailer. As such, there remains room for variation and improvement within the art.

BRIEF DESCRIPTION OF THE DRAWINGS

[0004] A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which:

[0005] Fig. 1 is a side view of a tractor hauling a trailer that includes an apparatus with skirts parallel to sides of the trailer in accordance with one exemplary embodiment.

[0006] Fig. 2 is a top view of Fig. 1.

[0007] Fig. 3 is a side view of a tractor hauling a trailer that has an apparatus in accordance with another embodiment that features angled skirts.

[0008] Fig. 4 is a top view of Fig. 3.

[0009] Fig. 5 is a side view of a tractor hauling a trailer that has an apparatus in accordance with another embodiment that features skirts with multiple angled sections.

[0010] Fig. 6 is a top view of Fig. 5.

[0011] Fig. 7 is a perspective view of a comer of an engaging top and side fairing in accordance with another embodiment.

[0012] Fig. 8 is a back view of the apparatus mounted onto a trailer.

[0013] Fig. 9 is a back view of the apparatus mounted onto a trailer that has top and side surfaces that are not even in height or width.

[0014] Fig. 10 is a side view of the apparatus mounted onto a trailer that has parallel front skirts.

[0015] Fig. 11 top view of Fig. 10.

[0016] Fig. 12 is a side view of the apparatus mounted onto a trailer in which a connecting portion is present between the front and rear skirts.

[0017] Fig. 13 is a top view of Fig. 12.

[0018] Fig. 14 is a side view of the rear trailer skirt mounted onto a trailer in which only a portion of the trailer is shown. [0019] Fig. 15 is a top cross-sectional view taken along line 15-15 of Fig. 14 in which the perimeter of the trailer is also noted on the drawing for reference.

[0020] The use of identical or similar reference numerals in different figures denotes identical or similar features.

DETAILED DESCRIPTION OF THE INVENTION

[0021] Reference will now be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, and not meant as a limitation of the invention. For example, features illustrated or described as part of one embodiment can be used with another embodiment to yield still a third embodiment. It is intended that the present invention include these and other modifications and variations.

[0022] The present invention provides for an apparatus 10 that achieves aerodynamic performance of a trailer 12 when driven by a tractor 42. The apparatus 10 includes a top fairing 14, a first side fairing 24, and a second side fairing 28 located at the back of the trailer 12. The side fairings 24, 28 may or may not engage the top fairing 14 such that a gap may or may not be present between them and a continuous surface may or may not extend from the side fairings 24, 28 onto the top fairing 14. In other words, the top fairing 14 could in some instances connect to both of the side fairings 24, 28 to form a continuous surface at the back section of the trailer 12, and in other instances gaps could be present between the side fairings 24, 28 and the top fairing 14. The apparatus 10 also includes first and second trailer skirts 32, 36 in addition to the top fairing 14 and side fairings 24, 28 to further enhance aerodynamic performance. Yet further, the apparatus 10 includes trailer rear skirts 78, 82 to achieve airflow properties upon normal use of the tractor 42 trailer 12. Additional features can be incorporated into the system the apparatus 10 comprises as will be discussed in order to achieve different aerodynamic properties of the trailer 12.

[0023] Figs. 1 and 2 show a tractor 42 with attached trailer 12 on the ground 92. In normal use, the tractor 42 is driven forward in the longitudinal direction 18 and aerodynamic features of the system are designed to handle this forward motion. Cross flow of air will be imparted onto the trailer 12 in the lateral direction 20 and the apparatus 10 may include features addressed to this cross-flow. The first side fairing 24 is located at the back of the trailer 12 in the longitudinal direction 18 and is mounted onto or over the first side surface 26 of the trailer 12. In a similar manner, the second side fairing 28 is mounted on or over the second side surface 30 of the trailer 12. The top fairing 14 is mounted on or over a portion of the top surface 16 of the trailer 12. The fairings 14, 24, 28 are located closer to the back end 80 of the trailer 12 in the longitudinal direction 18 than to the front of the trailer 12. In some instances, the fairings 14, 24, 28 could extend to the back end 80 of the trailer 12, and in yet other embodiments one or more of the fairings 14, 24, 28 could extend rearward of the back end 80 of the trailer 12 up to 3 inches in the longitudinal direction 18. The upper surfaces of the fairings 14, 24, 28 may have flat, angled, or curved sections so that airflow over them will achieve certain aerodynamic performance when the trailer 12 is driven. The top fairing 14 extends across the entire width of the top surface 16 in the lateral direction 20, but the side fairings 24, 28 extend along a majority of the height of the side surfaces 26, 30 in the vertical direction 22 but not along the entire height of the side surfaces 26, 30 in the vertical direction 22. In some instances, the fairings 24, 28 extend from 1/2 to 4/5 of the heights of the side surfaces 26, 30 in the vertical direction 22. This amount of coverage can be measured downward in the vertical direction 22 starting from the top surface 16. The fairings 14, 24, 28 are structures that can be curved panels that attach at a leading edge to the top surface 16 and side surfaces 26, 30 in such a way that the fairings 14, 24, 28 curve or otherwise extend away from the surface 16, 26, 30 in question and then curve or otherwise extend back to the surface 16, 26, 30 in question. This extension away from and then back to can be viewed in the forward to rearward direction in the longitudinal direction 18.

[0024] The side fairings 24, 28 engage the top fairing 14 in the discussed embodiment. This engagement may be along the entire lengths of the side fairings 24, 28 in the longitudinal direction 18 or may be less than along their entire lengths. There could be gaps in the engagement of the side fairings 24, 28 to the top fairing 14 along a portion of their lengths in some instances. Further, there could be cases where one or two of the fairings 14, 24, 28 are longer than the other one or two and in these instances there would be longitudinal sections that are not in engagement. Further, additional designs exist in which one of the two side fairings 24, 28 does not engage the top fairing 14 at all, but the other one of the two side fairings 24, 28 does in fact engage the top fairing 14. The engagement between the side fairings 24, 28 and the top fairing 14 may be form a 90 degree bend, or there could be convex surfaces between these components 14, 24, 28 that achieve a smoother transition at their engagement locations, or a combination of various geometric designs can be present at the points of engagement. Engagement of the top fairing 14 with at least one of the side fairings 24, 28 achieves a desired aerodynamic performance of the trailer 12 during normal use. The fairings 14, 24, 28 can be mounted onto the surfaces 16, 26, 30 through the use of screws, bolts, adhesives, mechanical fasteners or even through integral formation in some instances and may or may not engage the surfaces 16, 26, 30.

[0025] Trailer skirts 32, 36 are part of the apparatus 10 and work with the fairings 14, 24, 28 in achieving aerodynamic performance of the trailer 12. It has been discovered that the apparatus 10 having the fairings 14, 24, 28 work particularly well with the addition of the trailer skirts 32, 36 to the apparatus 10. The trailer skirts 32, 36 are located rearward of drive tires 44 of the tractor 42 in the longitudinal direction 18 and are located at the bottom of the trailer 12 and function to direct airflow at least partially from the bogie assembly 40 of the trailer 12. The trailer skirts 32, 36 are panels that have surfaces that can be variously shaped that direct airflow accordingly. The panels of the trailer skirts 32, 36 in Figs. 1 and 2 are parallel to the side surfaces 26, 30 of the trailer 12. In this regard, the trailer skirt 32 is closer to side surface 26 than to side surface 30 and is parallel to side surface 26. In a similar vein, trailer skirt 36 is closer to side surface 30 than to side surface 26 and is parallel thereto. The trailer skirts 32, 36 are located completely rearward of the drive tires 44 and completely forward of the bogie assembly 40 in the longitudinal direction 18. However, in other embodiments, a portion of the trailer skirts 32, 36 could extend to the bogie assembly 40 so that they are not completely forward of the bogie assembly 40. The trailer skirts 32, 36 can be connected or held onto the trailer 12 by any mechanism. For example, brackets 94 are present to bolt the trailer skirts 32, 36 onto the underside of the trailer 12.

[0026] The first trailer skirt 32 has a rearward most point 48 in the longitudinal direction 18 for redirecting airflow. Further, the first trailer skirt 32 has a forward most point 50 for redirecting airflow in the longitudinal direction 18. In evaluating the parallel nature of the first trailer skirt 32 to the first side surface 26, a first line 46 is drawn from the rearward most point 48 to the forward most point 50. The first side surface 26 is parallel to the longitudinal direction 18 in that the trailer 12 is box shaped and extends effectively in the longitudinal direction 18 regardless of whether the side surfaces 26, 30 are completely flat or have grooves or other features thereon. One can compare the angle the first line 46 makes to the line the first side surface 26 forms when viewed in the top view of Fig. 2 and ascertain that these two lines 46, 26 are parallel.

[0027] The second trailer skirt 36 has a rearward most point 54 that is the part of this component located most rearward in the longitudinal direction 18 that functions to redirect air. Likewise, the second trailer skirt 36 has a forward most point 56 for directing airflow in the longitudinal direction 18. A second line 52 can be drawn from the rearward most point 54 to the forward most point 56. The line that the second side surface 30 makes when viewed from the top in Fig. 2 is observed to be parallel to the second line 52. In this manner, the first and second trailer skirts 32, 36 can be said to be arranged in a parallel manner to the first and second side surfaces 26 and 30 and the panels that direct airflow are flat with no change in angular orientation. Although the two trailer skirts 32, 36 are arranged in a similar manner to one another, it is to be understood that in other versions of the apparatus 10 that one of the trailer skirts 32 could for instance be parallel to its side surface 26 while the other trailer skirt 36 is not parallel to its side surface 30.

[0028] Another configuration of the trailer skirts 32, 36 are illustrated in Figs. 3 and 4 in which a pair of skirts 32, 36 are again present and are located completely between the drive tires 44 and the bogie assembly 40 in the longitudinal direction 18. The panels making up the skirts 32, 36 are again flat along their entire lengths. The first trailer skirt 32 has a rearward most point 48 and a forward most point 50 with the first line 46 drawn between and connecting these points 48, 50 that matches the panel that directs airflow of the first trailer skirt 32. However, the first line 46 is not parallel to the line of the first side surface 26 as seen in the top view of Fig. 4. Instead, the first line 46 is oriented at an angle 34 to the first side surface 26. The angle 34 is 20 degrees. In other embodiments, the angle 34 may be from 0 degrees (parallel) up to and including 20 degrees. The angle 34 is measured in the direction of extension of the trailer skirt 32 forward in the longitudinal direction 18. The angle 34 is the angle of the panel of the first trailer skirt 32 that directs air to the first side surface 26 because this panel is the same as and overlaps the first line 46. As such, the first line 46 is measured in relation to the line created by the top view of the first side surface 26 and the angle 34 between these two lines is measured. Placement of the angle 34 in the 0-20 degree range allows for complimentary aerodynamic performance of the skirt 32 used in combinations with the fairings 10, 24, 28. In some embodiments, the forward most point 50 can sit from 0 to 20 inches inboard of the first side surface 26 in the lateral direction 20 towards the center of the trailer 12. The rearward most point 48 could sit from 0 to 8 inches inboard of the first side surface 26 in the lateral direction 20.

[0029] The second trailer skirt 36 has a second line 52 that is oriented at an angle 38 to the line of the second side surface 30 when viewed from the top in Fig. 4. This angle 38 is 20 degrees. In other embodiments, the angle 38 may be from 0 (parallel) to 20 degrees. The angle 38 can be the same as angle 34, or these angles 38, 34 can be different from one another in relation to the trailer 12 so that the skirts 32, 36 are not oriented at the same magnitude of angularity to their respective side surfaces 26, 30. The angle 38 is again measured by looking at the direction of extension of the second trailer skirt 36 forward in the longitudinal direction 18. The direction of extension of the second line 52 is noted upon moving forward in the longitudinal direction 18 from the rearward most point 54 to the forward most point 56. This second line 52 is compared to the line created by the second side surface 30 upon viewing it from above in Fig. 4 and the angle 38 is measured as the orientation between these two lines. The skirts 32, 36 are arranged so that they extend constantly inboard in the lateral direction 20 upon extension forward in the longitudinal direction 18. In this regard, at no point do the skirts 32, 36 extend outboard in the lateral direction 20, but instead only in the inboard direction as observed in the forward longitudinal direction 18. The forward most point 56 can sit from 0 to 20 inches inboard of the second side surface 30 in the lateral direction, and the rearward most point 54 may sit from 0 to 8 inches inboard of the second side surface 30.

[0030] Another version of the first and second trailer skirts 32, 36 is shown in Figs. 5 and 6. Unlike previous versions, the panels that make up the trailer skirts 32, 36 do not have flat surfaces across their entire lengths that direct the airflow. Instead, the skirts 32, 36 have sections that are oriented at different angles to one another and at different angles to the trailer 12. Although four such sections that change the angular orientation of the skirts 32, 36 are shown, fewer or more may be present. However, the panels that direct airflow still have a rearward most point 48, 54 and a forward most point 50, 56. The first and second lines 46, 52 are drawn through these points 48, 54, 50, 56 as previously discussed and the angles 34, 38 are calculated also as previously discussed. The panels making up the airflow surfaces of the skirts 32, 36 do not lie completely on these lines 46, 52 as in other embodiments but are for the most part out of sync with the lines 46, 52. A majority may be inboard of the lines 46, 52 in the lateral direction 20 in some embodiments, and in other embodiments a majority may be outboard of the lines 46, 52. As with other embodiments, the surfaces that direct airflow need not be flat, but could be curved and could have grooves or other features. The skirts 32, 36 could change their direction of orientation so that they are moving either inboard or outboard in the lateral direction 20 at different points. However, the lines 46, 52 still have a single angle 34, 38 for measurement even if localized portions of the skirts 32, 36 are oriented at different angles from one another and from that of the lines 46, 52. [0031] Fig. 8 shows a back view of the trailer 12 with attached apparatus 10. The top fairing 14 has an upper terminal point 58 that is the highest point of the top fairing 14 in the vertical direction 22. There may be a single upper terminal point 58 on the top fairing 14, or there may be multiple locations where the upper terminal point 58 is located. The height 60 of the top fairing 14 is measured from the top surface 16 of the trailer 12, at the same location at the upper terminal point 58 in the lateral direction 20, to the upper terminal point 58 in the vertical direction 22. The top surface 16 is a panel that covers the cargo area of the trailer. The top surface 16 near the back end 80 may have a rain gutter located thereon which would be an indentation on the top surface 16 that extends downward in the vertical direction 22. Other structural elements could be present at or on the top surface 16 near the back end. When describing the heights of the top fairings 14 and discussion of the associated top surfaces 16, it is to be understood that the heights are measured from the panel section of the top surface 16 and not from the rain gutters or other structural elements at or on the top surface 16. The side fairing 24 has an outer terminal point 62 located on its outer surface which is the portion of the side faring 24 farthest from the center of the trailer 12 in the lateral direction 20. There may be a single point on the outer surface of the side fairing 24 that is farthest and thus a single outer terminal point 62, or there may be multiple locations along the side fairing 24 that are farthest and thus a plurality of outer terminal points 62 are present. The width 64 of the side fairing 24 may be measured from the side surface 26, that is as the same vertical location as the outer terminal point 62 in the vertical direction 22, to the outer terminal point 62 in the lateral direction 20. The magnitude of the height 60 is greater than the magnitude of the width 64 in accordance with some exemplary embodiments. In a similar vein, the second side fairing 28 has a width 68 that is measured from the second side surface 30, that is at the same location in the vertical direction 22, to an outer terminal point 66 in the lateral direction 20. The outer terminal point 66 is the point of the outer surface of the second side fairing 28 that is farthest from the center of the trailer 12 in the lateral direction 20. The magnitude of the width 66 is less than the magnitude of the height 60 in accordance with some exemplary embodiments. In some instances, the magnitudes of the widths 64 and 68 are the same.

[0032] Fig. 9 shows an alternate embodiment in which the trailer 12 does not have flat side surfaces 26, 30 or a flat top surface 16 at least at locations onto which the apparatus 10 is mounted. The surfaces 26, 30, 16 could be grooved or have different areas of height/width. The area 70 of the top surface 16 engaged or covered by the top fairing 14 has a width 72 that extends in the lateral direction 20. The top fairing 14 extends into the grooves present on the top surface 16 so as to fill them in, but in other arrangements the grooves could be completely or partially empty. A highest location 96 of the top surface 16 is the location of the top surface 16 that is highest in the vertical direction 22. There may be a single highest location 96, or there may be multiple highest locations 96 along the width 72 of the area 70. The height 60 is measured from the highest location 96 to the upper terminal point 58 of the outer surface of the fairing 14 in the vertical direction 22. The side fairing 24 can be arranged in a similar manner in which an area 74 of the first side surface 26 has different inboard and outboard locations in the lateral direction 20 along an entire height 76 of the area 74. The entire height 76 is the height in the vertical direction 22 that the side fairing 24 engages or covers when the apparatus 10 is attached. One or more locations of the side surface 26 can have a maximum outboard location 98 in the lateral direction 20, and a most outboard location 98 is located on these one or more points of the side surface 26. In Fig. 9, the most outboard location 98 also has the same positioning in the vertical direction 22. The width 64 is measured from the most outboard location 98 to the outer terminal point 62 in the lateral direction 20. The magnitude of the height 60 may be greater than the magnitude of the width 64.

[0033] Also, the second side faring 28 can have a second side surface 30 that is not flat but instead features grooves or other depressions cut therein. The second side fairing 28 may cover or be inserted into some or all of the grooves on the second side surface 30 and includes an outer terminal point 66 which is the point of the second side faring 28 that is farthest from the center of the trailer 12 in the lateral direction 20. There may be a single outer terminal point 66, or multiple locations of the second side fairing 28 may include an outer terminal point 66. In a similar manner, the second side surface 30 may have a single or a plurality of maximum outboard locations 100 which are the portions of the second side surface 30 farthest from the center of the trailer 12 in the lateral direction 20. The outer terminal point 66 and the maximum outboard location 100 are at the same height in the vertical direction 22. The width 66 is measured from the outer terminal point 66 to the maximum outboard location 100 in the lateral direction. The magnitude of the width 66 is less than the magnitude of the height 60. In some instances, the magnitude of the width 66 is the same as the magnitude of the width 64.

[0034] An additional feature of the apparatus 10 is shown with reference to Figs. 1 and 2 in which a first trailer rear skirt 78 and a second trailer rear skirt 82 are present on the underside of the trailer 12. The rear skirts 78, 82 have panels that direct airflow to achieve a desired aerodynamic performance of the trailer 12 when driven. The rear skirts 78, 82 can work in combination with the first and second trailer skirts 32. The rear trailer skirts 78, 82 are located rearward of the first and second trailer skirts 32, 36 in the longitudinal direction 18 and in some instances may be located completely rearward of the bogie assembly 40 in the longitudinal direction 18. In some embodiments, there may be a gap of at least 2 meters between the rearward most points 48, 54 of the forward skirts 32, 36 and the forward most points of the first and second trailer rear skirts 78, 82 in the longitudinal direction 18. This gap between the forward skirts 32, 36 and the rearward skirts 78, 82 allow for access to the bogie assembly 40 tires and wheels and rear axle. The gap avoids interference with the bogie assembly 40, which can slide from a front location to a rear location in the longitudinal direction 18, when the bogie assembly is located in one of the forward locations and running to close to the back end 80.

[0035] In other instances, the rear trailer skirts 78, 82 are not completely behind the bogie assembly 40 but instead at least partially cover the bogie assembly 40 so that at least a portion of the bogie assembly 40 is located at the same position in the longitudinal direction 18 as portions of the first and second rear trailer skirts 32, 36. However, regardless of the positioning of the rear trailer skirts 78, 82 it may be the case that enough space is provided for accessing the bogie assembly 40 to allow for tire and wheel change. The bogie assembly 40 may be capable of sliding forward and rearward in the longitudinal direction 18 so this may effect relative placement between these components 40, 78 and 82 as well. Also, providing enough access to the bogie assembly 40 due to the presence of the when rear skirts 78, 82 may require one to take into account the positioning of the forward trailer skirts 32, 36 as well.

[0036] The rear trailer skirts 78, 82 may not extend to the back end 80 of the trailer 12 in the longitudinal direction 18. Instead, the rear trailer skirts 78, 82 can stop short of the back end 80 up to 0.5 meters from the back end 80 in the longitudinal direction so that a space no more than 0.5 meters exists from the back end 80 to the rearward longitudinal points of the first and second trailer rear skirts 78, 82 in the longitudinal direction 18. Of course, in other embodiments the rear trailer skirts 78, 82 can extend all the way to the back end 80 in the longitudinal direction 18 or to any extent short of or beyond the back end 80. The rear trailer skirts 78, 82 may be attached to the bottom of the trailer 12 via brackets 94 and can extend in the vertical direction 20 towards the ground 92 stopping short to allow sufficient clearance thereto. The embodiments in Figs. 1-4 all have 2 rear trailer skirts 78, 82 but a single one of the rear trailer skirts 78 or 82 could be present in other embodiments. In still further versions, the first rear trailer skirt 78 is configured differently than the second rear trailer skirt 82. The panels that make up the rear trailer skirts 78, 82 could be configured in the same manners as previously discussed with respect to the forward trailer skirts 32, 36 (for example the air directing panels are parallel to the first and second side surfaces 26, 30) and a repeat of this information is not necessary. In some instances, there may be a small angle associated with the rear trailer skirts 32, 36. This small angle may be an inward displacement at the rear 1/3 of the rear trailer skirts 78, 82 in the longitudinal direction 18. The amount of the displacement can be less than 3 inches inboard in the lateral direction 20. In other embodiments, the rear 1/3 is displaced 4 inches inboard from the side surfaces 26, 30 in the lateral direction 20. With respect to lateral placement of the rear trailer skirts 78, 82, they may be positioned not more than 2 inches inside of their respective side surfaces 26, 30 in the lateral direction 20. In other embodiments, the panels of the rear trailer skirts 78, 82 or portions thereof sit outside of the side surfaces 26, 30 by up to 2 inches. In some embodiments, the rear trailer skirts 78, 82 are parallel allowing for variation in from the side surfaces 26, 30 by 2 inches for the front 2/3 of the skirts 78, 82 in the longitudinal direction 18, and 4 inches from the side surfaces 26, 30 at the back edges of the skirts 78, 82 in the longitudinal direction 18. The lower extent of the trailer 12 can be tapered up to reduce the changes of impact with the ground 92 caused by the departure angle.

[0037] With reference back to Fig. 9, the intersection of the top fairing 14 with the side fairings 24, 28 includes two sharp 90 degree corners 84 at their intersection. In some embodiments, the corner 84 can be rounded and configured to adjust aerodynamic performance. A rounded comer 84 may achieve desired aerodynamic performance in relation to cross-winds imparted onto the trailer 12 through normal, forward use of the trailer 12 in the longitudinal direction 18. This reduction in drag from cross-winds may increase the fuel efficiency of the tractor 42 trailer 12 vehicle. Fig. 8 shows the comers 84 at the fairing 14, 24, 28 intersections being rounded instead of having a sharp edge. Both corners 84 can be configured to have the same size, shape, and features, or they may be different in different embodiments, especially when the first side fairing 24 is not the same as the second side fairing 28. The corners 84 can be described as being portions of the side fairings 24 and 28, can be portions of the top fairing 14, can be portions of all of the fairings 14, 24, 28, or may be separate components from the fairings 14, 24 and 28. However, the corner 84 should be configured so that at least some portion of the intersection of the top fairing 14 and the side faring 24 (and 28 in some embodiments) is continuous. The entire intersection between the fairings 14, 24, 28 need not be continuous in other versions.

[0038] Fig. 7 is a perspective view of a comer 84 that is present on the right hand side of the trailer 12 and is at the intersection of the second side fairing 28 and the top fairing 14. The corner 84 of Fig. 7 could be the one shown in the Fig. 8 embodiment, or the one shown in other presently disclosed embodiments. The comer 84 at the left hand side of the trailer 12 which is at the intersection of the top fairing 14 and the first side fairing 24 could be made in a similar manner and a repeat of this information is not necessary. In Fig. 7, the leading section 86 of the corner 84 is located at the forward most point of the corner 84 in the longitudinal direction 18. The tailing section 90 of the corner 84 in the longitudinal direction 18 is located at the rearward most position of the corner 84. In between these sections 86, 90 the middle section 88 of the corner 84 is located in the longitudinal direction 18. The comer 84 has a convex outer surface at all points from the leading section 86 to the tailing section 90. However, in other embodiments some portion of the corner 84 need not be convex but could be flat, angled, or concave in shape. The shape of the comer 84 is driven by the size and shape of the meeting fairing 14, 28 surfaces that converge at the corner 84. The radius of curvature of the surface at the leading section 86 may be the same as the radius of curvature of the surface at the tailing section 90, and these two radii of curvature may each be less than the radius of curvature of the surface of the comer 84 at the middle section 88. In some instances, the radius of curvature at the leading section 86 is 0.2 inches, the radius of curvature at the middle section is 5.0 inches, and the radius of curvature at the tailing section 90 is 0.2 inches.

[0039] Figs. 10 and 11 illustrate another embodiment of the apparatus 10. In this instance, the side fairings 24, 28 do not contact or otherwise engage the top fairing 14. The first side fairing 24 extends upwards along the majority of the height of the first side surface 26 but stops short of extending to the top surface 16 in the height direction 22 so that a gap exists between the side fairing 24 and the top fairing 14 causing these components not to engage one another. The second side fairing 28 is arranged in a similar manner in which it extends over a majority of the height of the second side surface 30 but not all the way up to the top surface 16 thus leaving a gap between the second side fairing 28 and the top fairing 14 causing these components not to engage one another. The apparatus 10 further includes the first and second trailer skirts 32, 36 and the first trailer rear skirt 78 and second trailer rear skirt 82.

[0040] Another embodiment of the apparatus 10 is shown in Figs. 12 and 13 in which the side fairings 24, 28 are again separate from and not contacting the top fairing 14. Further, the profile shapes of the fairings 14, 24, 28 are different in that the side fairings 24, 28 are more curved than other embodiments, and the top fairing 14 has a more straight angled upward extension to its upper terminal point 58 at which time it then assumes a curved, convex profile shape to its back end. Additionally, the fairings 14, 24, 28 do not terminate at the end of the trailer 12 in the longitudinal direction 18 but rather extend beyond the back end 80 so that they are all located rearward of the back end 18 in the longitudinal direction 18. The fairings 14, 24, 28 may each extend up to three inches rearward of the back end 80 in the longitudinal direction 18.

[0041] The apparatus again includes front trailer skirts 32, 36 and trailer rear skirts 78, 82 but in this embodiment they are connected by connecting portions 104, 106. The first trailer skirt 32 extends rearward in the longitudinal direction 18 to a rearward most point 48 that is forward of the bogie assembly 40 in the longitudinal direction 18. The connecting portion 104 extends rearward from the rearward most point 48 and covers some but not all of the height of the bogie assembly 40. The first trailer rear skirt 78 extends from the very back end 80 of the trailer forward in the longitudinal direction 18 to the bogie assembly 40 and covers a portion of the rear tires of the bogie assembly 40 from view relative to the side view in Fig. 12. The connecting portion 104 extends between the first trailer rear skirt 78 and the first trailer skirt 32 and has a height that is not as tall as either of these skirts 78, 32 in the vertical direction 22. Although some of the bogie assembly 40 is covered not all of the bogie assembly 40 is covered by the skirting thus allowing it to be accessed for tire or wheel repair. The components 32, 104 and 78 are all parallel to the first side surface 26 and form a single piece extending along the bottom of the trailer 12. These parts may in fact be one piece, or can be made of multiple pieces. The connecting portion 106, second trailer skirt 36 and the second trailer rear skirt 82 can be configured in manners just described with respect to their counterparts 32, 104, 78 on the opposite side of the trailer 12 and a repeat of this information is not necessary.

[0042] The connecting portions 104, 106 are not as tall as the skirts 32, 36, 78, 82 in the vertical direction 22. The connecting portions 104, 106 can make up a greater than 2 meter notch, as measured in the longitudinal direction 18, that allows for access to the tires and wheels of the bogie assembly 40. The connecting portions 104, 106 should only be able to extend downward to the middle of the center of the wheels in the vertical direction 22 to allow for bolts to be removed. Although a good portion of the tires are shown as covered in the figures, in other embodiments the connecting potions 104, 106 extend downward only so that the upper 2 inches of the tires of the bogie assembly 40 are covered. In accordance with certain embodiments, the connecting portions 104, 106 are located from 1 inch below the trailer side surfaces 26, 30 to 2 inches below the upper extent of the tires of the bogie assembly 40.

[0043] Figs. 14 and 15 show the rear section of the trailer 12 with emphasis on the first and second trailer rear skirts 78, 82. The skirts 78, 82 can be arranged so that the bogie assembly 40 is able to slide past. The skirts 78, 82 can have a front section in the lateral direction 18 that can have a narrow support profile to allow access for the bogie assembly 40. In this regard, they front sections of the skirts 78, 82 may not sit more than two inches inboard of the side surfaces 26, 30 in the lateral direction 20. The skirts 78, 82 may sit up to two inches outboard of the side surfaces 26, 30 in the lateral direction. The brackets 94 may be bifurcating brackets to allow for narrow support. The front sections of the skirts 78, 82, and in other instances the entire skirts 78, 82, can be parallel with their respective side surfaces 26, 30. The skirts 78, 82 can be variously positioned on the trailer such that the front section of the skirts 78, 82 that are the first 2/3 length of the skirts 78, 82 in the longitudinal direction 18 can be inboard of their respective side surfaces 26, 30 by up to two inches, and so that the rearward 1/3 of the skirts 78, 82 in the longitudinal direction 18 can be inboard up to four inches from their respective side surfaces 26, 30. In the Figs. 14 and 15 embodiments, the front 2/3 of the skirts 78, 82 are located outboard of their respective side surfaces 26, 30, and the rearward 1/3 of the skirts 78, 82 extend inboard in the lateral direction 20 until they terminate at their rearward ends inboard of the side surfaces 26, 30 in the lateral direction 20. The front 2/3 of the skirts 78, 82 are parallel to the side surfaces 26, 30, and the back 1/3 section of the skirts 78, 82 are angled to the side surfaces 26, 30. It is to be understood that other embodiments have the entire rear skirts 78, 82 parallel to the side surfaces 26, 30 and the back 1/3 of these skirts 78, 82 are not angled inward or outward in the lateral direction 20. In the preferred embodiment, the rear skirts 78, 82 are parallel because converging back skirts 78, 82 result in increasing the energy of air flow entering the wake behind the trailer 12.

[0044] The back sections of the skirts 78, 82 are tapered so as to reduce chances of the skirts 78, 82 impacting the ground 92 caused by the departure angle. Fig. 14 shows the back 1/3 section of the skirts 78, 82 angled upwards in the vertical direction 22 from the bottom edge of the forward 2/3 sections so that contact with the ground 92 is less likely.

[0045] The apparatus 10 may thus include the top fairing 14, side fairings 24 and 28, both of the forward trailer skirts 32, 36, and both of the trailer rear skirts 78, 82. The components of the apparatus 10 can be made so that they do not have any moving parts during standard, forward driving use of the trailer 12. The apparatus 10 may lack any parts that fold or flex during standard use. The apparatus 10 can be constructed so that it does not interfere with opening of the door at the back end 80. The apparatus 10 may improve fuel savings of the trailer 12 when used. The apparatus 10 can be arranged so that the tires of the bogie assembly 40 are not always covered and are observable due to a break in skirting in the longitudinal direction 18.

[0046] Testing of the apparatus 10 has been conducted in which the disclosed system exhibited an improvement in aerodynamic performance from an industry leading boat tail and skirt solution. Further, testing of the apparatus 10 has unexpectedly discovered that the coefficient of drag decreased from 0.49 to 0.395 at 65 miles per hour with 4.5 degrees of yaw (19.4%). This is a surprising result because a full length skirt even covering the wheels resulted in a 9.6% reduction in drag and end fairings 14, 24, 28 typically result in a 4% - 6% drag reduction. Thus even with the added drag of the gap present between the front skirts 32, 36 and the trailer rear back skirts 78, 82 the combination gains about a 5% drag improvement from this combination. One would expect the present design with the gap to perform worse than the full length skirt, but it does better. Further, the increase in performance is higher than the addition of full length skirt coverage 9.6% plus fairings 4%-6% (13.6%-15%) thus demonstrating that the apparatus 10 functions as a system in that the components achieve together in synergistic combination with one another a better performance than the sum of the individual components themselves.

[0047] While the present subject matter has been described in detail with respect to specific embodiments and methods thereof, it will be appreciated that those skilled in the art, upon attaining an understanding of the foregoing may readily produce alterations to, variations of, and equivalents to such embodiments. Accordingly, the scope of the present disclosure is by way of example rather than by way of limitation, and the subject disclosure does not preclude inclusion of such modifications, variations and/or additions to the present subject matter as would be apparent.